1. Field
The embodiments described herein relate to a semiconductor memory device.
2. Description of the Related Art
In recent years, several semiconductor memory devices having memory cells disposed three-dimensionally (stacked type semiconductor memory devices) have been proposed to increase the degree of integration of memory.
In one known example of such a stacked type semiconductor memory device, semiconductor pillars are formed extending in a perpendicular direction with respect to a semiconductor substrate, and word lines disposed in multiple layers in the perpendicular direction are connected to side surfaces of those semiconductor pillars via charge storage layers, thereby configuring a memory cell unit having memory cells connected in series in the perpendicular direction. The semiconductor pillars are disposed in a matrix in a column direction and a row direction on the semiconductor substrate, and bit lines are disposed along the semiconductor pillars aligned in the column direction. The charge storage layers are formed continuously along the side surfaces of the semiconductor pillars, hence manufacture is easy and appropriate for increasing integration. Improvements in manufacturing technology are expected to result in further improvements in performance due to miniaturization in this kind of stacked type semiconductor device.